Three-dimensional flexible containers of volumes of 50 liters or more, in many cases even 500 or 1000 liters or more, are needed for example in the biotech industry for media preparation, mixing of components, formulation and fill. The containers may serve as bioreactors, e.g., in the preparation of vaccines and gene therapy products. The containers may further be used in transportation and storage or as feed vessels.
Containers of such sizes, when filled with water or some other liquid, e.g., a biological broth, can have a weight of up to about 1500 kg or more. The hydraulic pressure created by the large volume of liquid held by the container results in a substantial stress on the seams of the container which, in an unsupported state, might be sufficient to cause rupture of the container.
Therefore, these large volume, three-dimensional flexible containers are not intended to be operated free standing, but rather, are designed to be accommodated in a rigid box-shaped support casing hereinafter referred to as a tote.
Necessarily, the tote and the flexible container should be in close contact with one another. It is desirable that the walls of the filled flexible container abut the side faces of the tote to reduce the forces resulting from the liquid in the container, especially those acting on the seams to a minimum.
The containers when delivered to the laboratory or production site where they are fit into the tote are in a collapsed folded state. Still their dimensions are quite big and therefore not easy to handle. However, proper positioning and correct orientation of the containers within the totes are of the essence not only in order to avoid problems with the unfolding flexible container like the formation of creases but also to provide the filled up containers within the totes in an optimal orientation such that the surrounding tote side faces can provide a maximum of support to the container walls and seams.
The pressures and forces associated with liquid volumes hold by the containers can cause the container seams to fail or rupture causing leakage of the container even if supported by the tote if the container is not properly positioned within the tote. The liquids held by the container are often enough containing highly valued ingredients. Accordingly, even minor leakages can cause substantive costs. Since a leakage of the container will compromise sterility the loss may not be limited to the portions of liquid seeping through the leakage but the entire contents of the container may be at stake.
In an attempt to provide a maximum support for the sidewalls of the container by the surrounding side faces of the tote US 2002/0131654 A1 suggests a design of those side walls of the container including seams such that in a filled state of the container they may adopt a bellied configuration without exerting additional stress onto the seams.
The correction of an improper orientation of a container within a tote is possible with reasonable effort and with a minor risk of damaging the same only in the beginning of the filling operation. However, having an operator pull a partially filled container to maneuver it into place is laborious and can cause failure of the container material by ripping.
Correct positioning of the container is additionally hampered by tubing which comes typically attached to the one or more ports of the container for simplified set up of the same in its laboratory or production environment. In a number of applications the tubing includes further accessory elements like filtering devices, clamps, vents or the like which make placement of the container within the tote even more troublesome.
It is an object of the invention to provide a container which requires minimal operator attention during set up and filling.